The question of whether there are any limits on scientific research has assumed an ever larger magnitude as scientists have devised ever more lethal means of annihilation and probed into the fascinating field of genetics. Some scientists assert there are no limitations on the broadening of knowledge. But in the wake of such events as Three Mile Island, Chernobyl, and the danger posed to all mankind by the Greenhouse Effect, both scientists and non-scientists have come increasingly to believe that there are what Joseph Fletcher calls "the moral limits of knowledge." In Mr. Fletcher's view "the humanist subordinates everything, including science and knowledge, to the test of human benefit...to assert that knowledge is always good is immoral, as well as unscientific. In the Western ethical heritage prudence has always been and still is a cardinal virtue."

Born in 1905, Joseph Fletcher has had a long and distinguished career as a theologian, philosopher, and humanist. He is a graduate of the Berkeley Divinity School and the University of London. He is the Robert Treat Paine Professor Emeritus of the Episcopal Theological School at Harvard University. For more than a decade he has served as the Visiting Scholar of Medical Ethics at the University of Virginia. He has lectured at more than 200 universities, colleges, schools, and seminaries throughout the world. His numerous books include The Church and Industry, Christianity and Property, and Morals and Medicine, a work published in 1954 and still widely in use.